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As overweight and obesity are a growing problem in industrialized societies, they become a main focus of many studies. The aim of this study was to determine whether there is an association between the occurrence of polymorphisms in serotonin-related genes and the prevalence of depressive symptoms in obese patients. Two polymorphisms were tested: a 44-bp insertion/deletion in the serotonin transporter (SERT) gene and a single-nucleotide variation (1438G/A) in the serotonin 2A receptor (5-HT2A) gene. The study involved 180 patients (41 men; 139 women) previously diagnosed as obese. All patients were subjected to clinical, biochemical, and neuropsychological evaluation and genotyping. Amplification of the gene fragments was obtained by the polymerase chain reaction (PCR) method. Products of the genotyping were separated via electrophoresis. The intensity of depressive symptoms was measured using the Beck Depression Inventory (BDI) and Hamilton Depression Scale (HAM-D). Clinically relevant depressive symptoms were diagnosed in 39% of subjects. The lowest intensities of depressive symptoms were ascertained in the group with the least advanced obesity, but this trend was statistically insignificant. Small differences were observed in obesity indicators among three groups of patients with various genotypes of the SERT gene, but these differences were also statistically insignificant. Furthermore, in the context of the intensity of depressive symptoms, no significant associations were observed in these two groups. Furthermore, no statistically significant differences were observed among specific obesity parameters and intensity of depressive symptoms as a function of the 5-HT2A gene polymorphism. To conclude, depressive symptoms were prevalent in obese participants: 39% of subjects experienced symptoms of clinical relevance. However, no significant associations were observed between 5-HT2A and SERT gene polymorphisms and depressive symptoms in this study group.

The electronic and magnetic properties of individual Fe atoms adsorbed on the surface of the topological insulator Bi$_2$Te$_3$(111) are investigated. Scanning tunneling microscopy and spectroscopy prove the existence of two distinct types of Fe species, while our first-principles calculations assign them to Fe adatoms in the hcp and fcc hollow sites. The combination of x-ray magnetic circular dichroism measurements and angular dependent magnetization curves reveals out-of-plane anisotropies for both species with anisotropy constants of $K_{\text{fcc}} = (10 \pm 4)$ meV/atom and $K_{\text{hcp}} = (8 \pm 4)$ meV/atom. These values are well in line with the results of calculations., 6 pages, 3 figures

A systematic study of LaMn 1− x Co x O 3 perovskite series by means of X-ray absorption spectroscopy in the extended X-ray absorption fine structure (EXAFS) range of the K-absorption edge of Mn is reported. The Mn–K edge absorption measurements in the EXAFS region were performed to study the local surrounding of Mn ions. Polycrystalline powder samples of LaMn 1− x Co x O 3 ( x =0, 0.02; 0.2; 0.4; 0.5; 0.6; 0.8) prepared by solid-state reaction were used. The EXAFS spectra were analyzed with the FEFF8 computer program. The Mn–O distances of Mn to the nearest oxygen surroundings were evaluated for the samples in the series and compared with the Co–O distances obtained by EXAFS in V. Prochazka et al., JMMM 310 (2007) 197 and with results of X-ray powder diffraction in C. Autret, J. Phys. Condens. Matter 17 (2005) 1601.

A 55Mn and 139La NMR study of La0.35Ca0.65MnO3 is reported. The zero field 55Mn spectra consist of two lines centered at 290 and 375 MHz. Their behavior under an applied magnetic field makes it possible to attribute them to regions of antiferromagnetically and ferromagnetically coupled Mn spins, respectively. This gives evidence for the existence of electronic phase segregation of microscopic ferromagnetic regions of double exchange coupled Mn spins over a charge ordered antiferromagnetic background. The behavior of these ferromagnetic regions in the applied magnetic field is related to the magnetoresistive properties of the manganites.

We report the study of lattice effects in the Mott insulator HoVO3 performed by means of linear thermal expansion on a single crystal in the temperature range 10-290 K. The holmium orthovanadate HoVO3 reveals gradual orbital ordering (OO) below T-OO = 200K and orders antiferromagnetically at T-N = 113 K. A first-order structural phase transition takes place at T-S similar to 38 K, which is probably accompanied by change of the OO type and hence the type of antiferromagnetic spin ordering. (c) 2007 Elsevier B.V. All rights reserved.

The relation between nanoscale structure, local atomic order and magnetic properties of (FeCoZr)(x)(CaF2)(100-x) (29 LT = x LT = 73 at. %) granular films is studied as a function of metal/insulator fraction ratio. The films of a thickness of 1-6 mu m were deposited on Al-foils and glass-ceramic substrates, by ion sputtering of targets of different metal/insulator contents. Structural characterization with X-ray and electron diffraction as well as transmission electron microscopy revealed that the films are composed of isolated nanocrystalline bcc alpha-FeCo(Zr) alloy and insulating fcc CaF2 matrix. They grow in a columnar structure, where elongated metallic nanograins are arranged on top of each other within the columns almost normal to the substrate surface. Mossbauer spectroscopy and magnetometry results indicate that their easy magnetization axes are oriented at an angle of 65 degrees-74 degrees to the surface in films with x between 46 and 74, above the electrical percolation threshold, which is attributed to the growth-induced shape anisotropy. Interatomic distances characteristic for metallic state of alpha-FeCo(Zr) nanograins were revealed by X-ray Absorption Spectroscopy. The results show a lack of surface oxidation of the alloy nanograins, so the growth-induced orientation of nanograins in the films cannot be attributed to this effect. The study is among the first to report a growth-induced non-planar magnetic anisotropy in metal/insulator granular films above the percolation threshold and to reveal the origin of it. (C) 2014 AIP Publishing LLC.

In this paper we report on the lattice effects in the Mott insulator yttrium orthovanadate (YVO3). Linear thermal expansion and magnetostriction experiments have been performed on a single crystal, in the temperature range from 5 K to room temperature. The YVO3 orders antiferromagnetically at TN=116 K and orbital ordering was reported to appear below TOO=196 K. A first-order structural phase transition takes place at TS=77 K, accompanied by changes in the antiferromagnetic type of ordering as well as in the orbital-ordering type. Our results reveal that the thermal expansion measurement technique is a very powerful tool in order to clearly detect the existence of the above-mentioned transitions. The magnetostriction results point to the stability of the low-temperature-magnetic ground state under such high applied magnetic field., Authors acknowledge financial support by the European Project SCOOTMO RTN, (Contract No. HPRN-CT-2002-00293).

Non-magnetic Pt catalysts, supported on carbon coated magnetic Co nanoparticles, changed catalytic performance in the presence of an external magnetic field. This behavior relates to an electronic change of Pt induced by a localized magnetic field, which modifies the CO adsorption geometry. In situ resonant inelastic X-ray scattering (RIXS) experiments and theory reveal the change of atop CO adsorption geometry on the Pt catalyst to bridged geometry under an external magnetic field. This observation opens the possibility of catalytic control by means of an external magnetic field.

Dopamine is considered to be crucial for food craving and intake, drug abuse and electrical brain stimulation. Increased levels of dopamine occur after energy intake in the dorsal striatum. In the ventral tagmental area, dopamine is responsible for motivation. There is a natural synaptic dopamine level, and as a result its activity is controlled by density of receptors, amount of released neurotransmitter, and defectiveness of re-uptake by specific transporters. In our study, we wanted to investigate if there is a correlation between mean BMI values and VNTR polymorphisms in SLC6A3 (rs28363170) and DRD4 genes.Chosen gene fragments were amplified using polymerase chain reaction on the DNA template obtained from 506 women. The products of the reaction were electrophoresed and visualised in 3% agarose gel. The genotyping data was analysed with Kruskal-Wallis tests (p 〈 0.05).In the case of SLC6A3, statistically significant differences in mean BMI were found in the group of obese women (p 〈 0.05) but not for the whole population of women with normal weight or with overweight (p 〉 0.05). The mean BMI was higher for the SS genotype than for combined LL and LS genotypes. The difference in mean BMI values for variants of DRD4 was significant for the whole studied population and in the obese group (p 〉 0.05), and the higher value was correlated with the presence of a variant with seven or more repeats of 48 bp motif.When the two analysed polymorphisms were combined, the spread between the mean BMI values became greater than for single genes. This suggests that the effect on body mass of these two polymorphisms may combine and cause hypo-functionality of the dopaminergic reward system.

A nuclear magnetic resonance study of the A2FeMO6 (A=Ba, Sr, Ca; M=Mo, Re) double perovskites is reported. Spin echo spectra have been measured at 4.2 K and zero external magnetic field. Resonant signals at Mo nuclei are observed at 30–80 MHz and at 750–1000 MHz for Re nuclei. Frequencies of the main lines correspond to Mo hyperfine fields of 19, 24 and 23 T and to Re hyperfine fields of 84, 94 and 95 T for Ba, Sr and Ca compounds, respectively. From these data the values of Mo and Re magnetic moments are derived and the relation to the results of theoretical calculations is discussed.

A study of La influence on molybdenum and iron magnetic states in the Sr 1−3 x Ba 1+ x La 2 x FeMoO 6 series ( x =0, 0.1, 0.2, 0.3) is reported. The main line and a low frequency satellite of the Mo NMR spectra are attributed to ideal and defect sites. The structure of the main line with increasing La content indicates a local effect of electron doping on Mo sites. Fe:K edge X-ray magnetic circular dichroism spectra show an increased polarisation of the Fe 4p states with La doping. The Fe:K absorption edges show an unchanged Fe ionic state but an increased localisation of the Fe electronic states.

Field dependences of the magnetic circular dichroism at the Mn:K edge and RE:L2,L3 edges in colossal magnetoresistive perovskites La0.67−yREyCa0.33MnO3 (y=0, Tb-doped y=0.1, 0.22 and Nd-doped y=0.33) are reported. Ferromagnetically ordered compounds show a similar dependence for the Mn and RE magnetic sublattices, in contrast to the cluster glass (y=0.22) compound which revealed a weaker Mn–RE magnetic coupling. By comparison of X-MCD and VSM magnetometry an estimate of the relative amount of manganese atoms in the metallic ferromagnetic regions is obtained.

A 55 Mn nuclear magnetic resonance study of a layered perovskite La1.4Sr1.6Mn2O7 is reported. Between 4.2 K and the magnetic ordering temperature, 100 K , zero field spin echo spectra consist of signals corresponding to the double-exchange (DE) states and charge localized Mn3+, Mn4+ states. This indicates occurrence of electronic and magnetic phase segregation into ferromagnetic metallic and ferromagnetic insulating regions. Above 100 K a DE line is observed, revealing the presence of long lived metallic clusters. The relation of results to magnetoresistive properties of the compound is discussed.

The nanoscopic magnetoelectronic phase separation in doped La${}_{1\ensuremath{-}x}$Sr${}_{x}$CoO${}_{3}$ perovskites was studied with local probes. The phase separation is directly observed by M\"ossbauer spectroscopy in the studied doping range of 0.05 $\ensuremath{\le}$ $x$ $\ensuremath{\le}$ 0.25 both at room temperature and in the low-temperature magnetic phase. Extended with current synchrotron-based x-ray spectroscopies, these data help to characterize the volume as well as the local electric and magnetic properties of the distinct phases. A simple model based on a random distribution of the doping Sr ions describes well both the evolution of the separated phases and the variation of the Co spin state. The experiments suggest that Sr doping initiates small droplets and a high degree of doping-driven cobalt spin-state transition, while the Sr-free second phase vanishes rapidly with increasing Sr content.

International audience; X-ray Magnetic Circular Dichroism is measured at the Fe K pre-edge in Yttrium Iron Garnet using two different procedures that allow reducing the intrinsic broadening due to the 1s corehole lifetime. First, deconvolution of XMCD data measured in Total Fluorescence Yield (TFY) with an extremely high signal-to-noise ratio enables to gain a factor of 2.4 in the XMCD intensity. Ligand Field Multiplet calculations performed with different values of intrinsic broadening show that deconvolving such high quality XMCD data is similar to reducing the lifetime broadening from a 1s corehole to a 2p corehole. Second, MCD is measured by Resonant Inelastic X-ray Scattering spectroscopy as a function of incident energy and emission energy. Selection of a fixed emission energy, instead of using the TFY, allows enhancing the MCD intensity up to a factor of ∼4.7. However, this significantly changes the spectral shape of the XMCD signal, which cannot be interpreted any more as an absorption spectrum.

A linac delivering intensity-modulated radiotherapy (IMRT) can benefit from a flattening filter free (FFF) design which offers higher dose rates and reduced accelerator head scatter than for conventional (flattened) delivery. This reduction in scatter simplifies beam modeling, and combining a Monte Carlo dose engine with a FFF accelerator could potentially increase dose calculation accuracy. The objective of this work was to model a FFF machine using an adapted version of a previously published virtual source model (VSM) for Monte Carlo calculations and to verify its accuracy.An Elekta Synergy linear accelerator operating at 6 MV has been modified to enable irradiation both with and without the flattening filter (FF). The VSM has been incorporated into a commercially available treatment planning system (Monaco™ v 3.1) as VSM 1.6. Dosimetric data were measured to commission the treatment planning system (TPS) and the VSM adapted to account for the lack of angular differential absorption and general beam hardening. The model was then tested using standard water phantom measurements and also by creating IMRT plans for a range of clinical cases.The results show that the VSM implementation handles the FFF beams very well, with an uncertainty between measurement and calculation of1% which is comparable to conventional flattened beams. All IMRT beams passed standard quality assurance tests with95% of all points passing gamma analysis (γ1) using a 3%/3 mm tolerance.The virtual source model for flattened beams was successfully adapted to a flattening filter free beam production. Water phantom and patient specific QA measurements show excellent results, and comparisons of IMRT plans generated in conventional and FFF mode are underway to assess dosimetric uncertainties and possible improvements in dose calculation and delivery.

The NMR spin-echo spectra measured on a powder sample of Sr2FeMoO6 at 3 and 77 K at zero field and in an applied magnetic field are reported. The main resonance line at 68.5 MHz in zero magnetic field at 3 K is identified as originating from 95Mo and 97Mo. The resonance frequency and its shift in the applied field correspond to a hyperfine field of 24 T at the Mo nucleus, parallel to the magnetisation. This large field indicates the presence of a magnetic moment of the order of 0.6 μB at the Mo site antiparallel to the Fe moments. The relation of the results to the magnetoresistive properties of the material is discussed.

V${}_{2}$O${}_{3}$ is an archetypal system for the study of correlation-induced, Mott-Hubbard metal-insulator transitions. Despite decades of extensive investigations, the accurate description of its electronic properties remains an open problem in the physics of strongly correlated materials, also because of the lack of detailed experimental data on its electronic structure over the whole phase diagram. We present here a high-resolution x-ray absorption spectroscopy study at the V $K$ edge of (V${}_{1\ensuremath{-}x}$Cr${}_{x}$)${}_{2}$O${}_{3}$ to probe its electronic structure as a function of temperature, doping, and pressure, providing an accurate picture of the electronic changes over the whole phase diagram. We also discuss the relevance of the parallel evolution of the lattice parameters, determined with x-ray diffraction. This allows us to draw two conclusions of general interest: First, the transition under pressure presents peculiar properties, related to a more continuous evolution of the lattice and electronic structure; second, the lattice mismatch is a good parameter describing the strength of the first-order transition, and is consequently related to the tendency of the system toward the coexistence of different phases. Our results show that the evolution of the electronic structure while approaching a phase transition, and not only while crossing it, is also a key element to unveil the underlying physical mechanisms of Mott materials.

We discuss a truly bulk sensitive, $j$-selective probe of the valence and conduction bands of the $5d$ transition metal systems. The electronic structure of Re and W oxides, with formal occupation of $d$-states ranging from $5d$${}^{0}$ to $5d$${}^{3}$, was investigated by means of resonant x-ray emission spectroscopy (RXES) across the L${}_{3}$ and L${}_{2}$ edges of Re (\ensuremath{\sim}10.5 and \ensuremath{\sim}12 keV, respectively) and W (\ensuremath{\sim}10 and \ensuremath{\sim}11.5 keV, respectively). We present a systematic theoretical analysis of the RXES spectra within a density functional theory band structure approach. Excellent agreement between experiment and theory is achieved, demonstrating that the theory accounts for the most relevant interactions within the experimental energy bandwidth (\ensuremath{\sim}2--3 eV). Differences between the L${}_{3}$ and the L${}_{2}$ edges can be reproduced by considering spin-orbit interaction. The possible applications and limitations of our approach are discussed.

Measurement of the Ce valence in the heavy fermion ${\mathrm{CeCu}}_{2}{\mathrm{Si}}_{2}$ is reported for the first time under pressure and at low temperature ($T=14\text{ }\text{ }\mathrm{K}$) in proximity of the superconducting region. ${\mathrm{CeCu}}_{2}{\mathrm{Si}}_{2}$ is considered as a strong candidate for a new type of pairing mechanism related to critical valence fluctuations which could set in at high pressure in the vicinity of the second superconducting dome. A quantitative estimate of the valence in this pressure region was achieved from the measurements of the Ce ${L}_{3}$ edge in the high-resolution partial-fluorescence yield mode and subsequent analysis of the spectra within the Anderson impurity model. While a clear increase of the Ce valence is found, the weak electron transfer and the continuous valence change under pressure suggests a crossover regime with the hypothetical valence line terminating at a critical end point ${T}_{\mathrm{cr}}$ close to zero.

Metal-doped amorphous carbon films (a-C:Me) were deposited at room temperature by magnetron sputtering using a metal (Me = Ti, V, Zr, W) and a graphite target. The metal distribution and the temperature-induced carbide crystallite formation were analyzed by X-ray diffraction (XRD), electron microscopy (TEM, STEM) and X-ray absorption spectroscopy (EXAFS, XANES), focusing on low metal concentrations between 6.5 and 9.5%. In as-deposited samples, the metal atoms are atomically distributed in the carbon matrix without significant formation of carbide particles. With annealing to 900 K the local atomic environment around the metal atoms becomes similar to the carbide. The carbide crystallites grow with annealing up to 1300 K, their size is dependent on the metal type: V > Ti > Zr≈W. W2C and WC1 − x crystallites were identified for W-doped films, whereas the monocarbides are formed for the other metals. It is demonstrated, that EXAFS and high resolution electron microscopy are required to get a correct picture of the structure of the analyzed a-C:W films.

The changes in the electronic structure of V2O3 across the metal-insulator transition induced by temperature, doping, and pressure are identified using high resolution x-ray absorption spectroscopy at the V pre-K edge. Contrary to what has been taken for granted so far, the metallic phase reached under pressure is shown to differ from the one obtained by changing doping or temperature. Using a novel computational scheme, we relate this effect to the role and occupancy of the a{1g} orbitals. This finding unveils the inequivalence of different routes across the Mott transition in V2O3.

We report a new method to introduce metal atoms into silicon wafers, using negligible thermal budget. Molecular thin films are irradiated with ultra-violet (UV) light releasing metal species into the semiconductor substrate. Secondary ion mass spectrometry (SIMS) and X-ray absorption spectroscopy (XAS) show that Mn is incorporated into Si as an interstitial dopant. We propose that our method can form the basis of a generic low-cost, low-temperature technology that could lead to the creation of ordered dopant arrays., 12 pages, 3 figures

Spin and orbital contributions to the magnetic moment of rhenium have been studied across the magnetostructural transition in ${\text{Ca}}_{2}{\text{FeReO}}_{6}$ double perovskite employing x-ray magnetic circular dichroism (XMCD) at the $\text{Re}\text{ }{L}_{2,3}$ edges. Temperature-dependent measurements performed in pulsed magnetic field varying from 6.8 to 30 T revealed that the two phases of this compound are characterized by a different spin-orbit coupling. At $T=10\text{ }\text{K}$, the average orbital-to-spin moment ratio of the Re sublattice increases in the application of 30 T magnetic field by $\ensuremath{\sim}5%$, while at $T=250\text{ }\text{K}$ it is field independent and amounts to $|{m}_{L}/{m}_{S}|=0.362(6)$. The field and temperature dependences of the rhenium XMCD and bulk magnetization are explained within the scenario of a field-induced phase coexistence and transition between two monoclinic phases of diverse magnetocrystalline coupling.

We have developed a versatile experimental apparatus for synchrotron x-ray measurements in pulsed high magnetic fields. The apparatus consists of a double cryostat incorporating a liquid nitrogen bath to cool the miniature pulsed coil and an independent helium flow cryostat allowing sample temperatures from 4 up to 250 K. The high duty cycle miniature pulsed coils can generate up to 38 T. During experiments at 30 T a repetition rate of 6 pulsesmin was routinely reached. Using a 4 kJ power supply, the pulse duration was between 500 mus and 1 ms. The setup was used for nuclear forward scattering measurements on 57Fe up to 25 T on the ESRF beamline ID18. In another experiment, x-ray magnetic circular dichroism was measured up to 30 T on the ESRF energy dispersive beamline ID24.

A spin-selective and polarization dependent study at the $K$ absorption pre-edge in hematite $(\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{Fe}}_{2}{\mathrm{O}}_{3})$ was performed by means of $1s3p$ resonant x-ray emission spectroscopy on a single crystal. The experimental results can be modeled using a band structure approach [local density approximation (LDA + $U$)]. The spin-selective spectra in connection with the calculations firmly establish metal-oxygen and metal-metal orbital hybridizations. A phase shift in the polarization dependent absorption cross section is observed between the first two absorption features showing directionality in the orbital hybridization.

The present paper demonstrates the feasibility of X-ray absorption spectroscopy (XAS) and X-ray magnetic circular dichroism (XMCD) under high magnetic fields up to 26 T and low temperatures down to 5 K on the ID24 energy-dispersive XAS beamline of the ESRF. The pulsed magnetic field set-up, entirely developed at the ESRF, is described as well as the beamline set-up, the synchronization and the measurement procedure. It allows field strengths up to 30 T. Finally, as an example, we report a recent XMCD study at the Re L2 and L3 absorption edges of the double perovskite Sr2CrReO(6).

Spectroscopic techniques that aim to resolve the electronic configuration and local coordination of a central atom by detecting inner-shell radiative decays following photoexcitation using hard X-rays are presented. The experimental setup requires an X-ray spectrometer based on perfect crystal Bragg optics. The possibilities arising from non-resonant (X-Ray Emission Spectroscopy - XES) and resonant excitation (Resonant Inelastic X-Ray Scattering Spectroscopy – RIXSS, High-Energy-Resolution Fluorescence Detected (HERFD) XAS) are discussed when the instrumental energy broadenings of the primary (beamline) monochromator and the crystal spectrometer for x-ray emission detection are on the order of the core hole lifetimes of the intermediate and final electronic states. The small energy bandwidth in the emission detection yields line-sharpened absorption features. In transition metal compounds, electron-electron interactions as well as orbital splittings and fractional population can be revealed. Combination with EXAFS spectroscopy enables to extent the k-range beyond unwanted absorption edges in the sample that limit the EXAFS range in conventional absorption spectroscopy.

Two novel non-stoichiometric 3D cyano-bridged coordination networks of general formula CuII2+x{CuII4[WV(CN)8]4−2x[WIV(CN)8]2x}·yH2O were obtained according to two different synthetic strategies. The heterogeneous reaction between solid 2D cyano-bridged network (dienH3){CuII[WV(CN)8]}3·4H2O (1) (dienH33+ = protonated diethylenetriamine) and an aqueous solution of DyIII(NO3)3 results in the removal of dienH33+ cations and the formation of a 3D cyano-bridged CuII2.44{CuII4[WV(CN)8]3.12[WIV(CN)8]0.88}·5H2O (2) network. The direct combination of [CuII(H2O)6]2+ and [WV(CN)8]3− in aqueous media leads to the structurally related CuII2.97{CuII4[WV(CN)8]2.06[WIV(CN)8]1.94}·4H2O (3) assembly. The assemblies 2 and 3 were characterised by X-ray powder diffraction along with IR, X-ray absorption spectroscopy (XAS), proton induced X-ray emission (PIXE) and magnetic measurements. 2 and 3 crystallise in a tetragonal system, space group I4/mmm with cell parameters a = b = 7.2695(9) A; c = 28.268(5) A; Z = 2 (2) and a = b = 7.2858(9) A, c = 28.282(5) A, Z = 2 (3). Both networks are characterised by the increase of TC from 33 K to 40 K and coercivity from 0.2 to 2–2.5 kOe compared to 1. Despite their general structural and magnetic similarity, 2 and 3 reveal significant differences in magnetic dimensionality: compound 2 exhibits the features of a metamagnet with a threshold field of 1.8 kOe at 4.2 K, while compound 3 resembles a classical magnet with 3D ordering. This difference is discussed in terms of non-stoichiometry of the networks accompanied by the appearance of different numbers of non-magnetic “defects” due to the formation of diamagnetic W(IV) centres.

An experimental and theoretical study of the K absorption pre‐edge in hematite (α‐Fe2O3) is presented. Resonant inelastic X‐ray scattering with a 3p hole in the final states was used to obtain spin‐selective absorption spectra. Spectral variations with changing the orientation of the incident X‐ray polarization vector with respect to the crystal c‐axis in single crystalline hematite are discussed. The experimental results can be successfully modeled using a band‐structure approach (WIEN2k with LDA+U). A pre‐edge absorption feature is assigned to unoccupied p electronic states due to Fe‐Fe interactions, i.e. they are due to non‐local transitions.

When designing communication systems based on serially concatenated codes and iterative decoding, it is common practice to use recursive convolutional codes as inner codes. In this paper we show that very good performance can also be obtained by using simple block codes as inner codes. In particular, we propose a simple extension of a single parity check encoder that produces large Hamming weight output sequences for weight one input sequences. We also present a soft decoding algorithm and use a uniform interleaver analysis and EXIT charts to design efficient schemes that perform well in both the waterfall and error floor regions of the bit error rate curve.

A systematic study of the valence states of Mn and Co in the perovskite series ${\mathrm{LaMn}}_{1\ensuremath{-}x}{\mathrm{Co}}_{x}{\mathrm{O}}_{3}\phantom{\rule{0.3em}{0ex}}(x=0\phantom{\rule{0.3em}{0ex}}\mathrm{to}\phantom{\rule{0.3em}{0ex}}1)$ by means of x-ray absorption near edge spectroscopy (XANES) at the K-edges is presented. The chemical shift and the evolution of the pre-edge features reveal a gradual increase of the average oxidation level of both, Mn and Co ions, with Co doping, which suggests that mixed valence states of ${\mathrm{Co}}^{2+}∕{\mathrm{Co}}^{3+}$ and ${\mathrm{Mn}}^{3+}∕{\mathrm{Mn}}^{4+}$ exist in the whole solid solution range. The relation of the results to the magnetic properties of the compounds is discussed.

Two new ferromagnetic organic-inorganic hybrid materials [Co(II)3(H2O)6(pyz)3[W(V)(CN)8]2].3.5H2O (1) and [Co(II)3(H2O)4(4,4'-bpy)3[W(V)(CN)8]2].1.5(4,4'-bpy).6H2O (2) have been synthesised and characterised. The structure of the compounds have been investigated combining EXAFS (extended X-ray absorption fine structure), ES-MS (electrospray mass spectrometry), IR (infrared spectroscopy), UV-VIS electronic spectroscopy and TGA (thermogravimetric analysis) coupled with QMS (quadrupole mass spectrometer) experiments. The studies reveal that both compounds consist of Co(II)-NC-W(V) and Co(II)-L-Co(II) linkages (L = pyrazine (1) or 4,4-bipyridine (2)). Both networks are created by cyano-bridged Co(II)3W(V)2 chains joined by organic linkers into a 2D architecture. A difference of cobalt coordination numbers in both compounds derived from EXAFS study is consistent with the ES-MS conclusion. The ac magnetic characterisation exhibits the transition to the ferromagnetic phase at T(C) = 26 K (1) and to the spin glass-like phase at T(G) = 16 K (2). The frequency dependent chi'(T) and chi''(T) signals indicate the presence of some disorder in spin alignment below ordering temperatures. Both networks are also characterised a by magnetic hysteresis loop of coercive field H(c) = 750 Oe (1) and 1200 Oe (2) at T = 4.2 K.

An NMR study of polycrystalline ${\mathrm{Pr}}_{0.5}{\mathrm{Ca}}_{0.5}{\mathrm{Mn}}_{1\ensuremath{-}x}{\mathrm{Ga}}_{x}{\mathrm{O}}_{3}$ ($x=0$ and 0.03) and ${\mathrm{Pr}}_{0.67}{\mathrm{Ca}}_{0.33}{\mathrm{MnO}}_{3}$ at 3 K is presented. Zero-field spin-echo spectra of the Ga-doped compound consist of an overlapping $^{69,71}\mathrm{Ga}$ signal at 74 MHz (hyperfine field of 5.3 T) and a $^{55}\mathrm{Mn}$ double-exchange (DE) line at 375 MHz (35.5 T). Measurements in an applied field show a steplike increase in the DE line intensity, which corresponds to an increase of the amount of the ferromagnetic metallic phase. This coincides with a steplike feature in the bulk magnetization measurements. The effect is similar to that in the previous field-dependent $^{55}\mathrm{Mn}$ NMR measurements of ${\mathrm{Pr}}_{0.67}{\mathrm{Ca}}_{0.33}{\mathrm{MnO}}_{3}$. The insulator - metal transition for ${\mathrm{Pr}}_{0.67}{\mathrm{Ca}}_{0.33}{\mathrm{MnO}}_{3}$, at ambient pressure, occurs at fields greater than 5 T; however, at 1.1 GPa, the DE line corresponding to the ferromagnetic metallic phase is already present at zero field.

The temperature dependence of the crystal structure and electronic properties of brownmillerite-like Ca(2.5)Sr(0.5)GaMn(2)O(8) has been studied by neutron powder diffraction and muSR spectroscopy. The results show that short-range 2D magnetic order begins to develop within the perovskite-like bilayers of MnO(6) octahedra approximately 50 K above the 3D Néel temperature of approximately 150 K. The bilayers show a structural response to the onset of magnetism throughout this temperature range whereas the GaO(4) layers that separate the bilayers only respond below the 3D ordering temperature. XANES spectroscopy shows that the sample contains Mn(3+) and Mn(4+) cations in a 1:1 ratio, and the behavior in the region of the Néel transition is interpreted as a local charge ordering. Electron diffraction and high-resolution electron microscopy have been used to show that the local microstructure is more complex than the average structure revealed by neutron diffraction, and that microdomains exist in which the GaO(4) tetrahedra show different orientations. It is argued that the bonding requirements of diamagnetic gallium control the electronic behavior within the perovskite-like bilayers.

In this work we show the very different nature of the ferromagnetic state of the low-hole-doped manganites with respect to other manganites showing colossal magnetoresistance. High-field measurements definitively prove the coexistence of ferromagnetic-metallic and ferromagnetic-insulating regions even when the sample is magnetically saturated, with the ground state being inhomogeneous. We have investigated ${\mathrm{La}}_{0.9}{\mathrm{Ca}}_{0.1}{\mathrm{MnO}}_{3}$ as a prototype compound. A wide characterization by means of magnetic and magnetotransport measurements, neutron diffraction, small-angle neutron scattering, and nuclear magnetic resonance has allowed us to establish that the ground state is based on the existence of disordered nanometric double-exchange metallic clusters that coexist with long-range superexchange-based ferromagnetic insulating regions. Under high magnetic field the system reaches magnetization saturation by aligning the magnetic clusters and the insulating matrix, but even if they grow in size, they do not reach the percolation limit.

Interaction of ultrafast (∼ 50 fs), high intensity (up to 1013 W/cm2) XUV (λ ∼ 85 nm) FEL beam with solids has been studied at the TTF-FEL facility. Damaged surfaces have been investigated using light, electron, and atomic force microscopy. Influence of the FEL radiation intensity on the structural changes at the surfaces has been investigated. Results obtained for different materials, i. e. metals (Au), semiconductors (Si), inorganic insulators (Ce:YAG, BaF2, SiO2), and organic polymers (polymethylmethacrylate - PMMA), are compared. Laser-induced periodic surface structures (LIPSS) were observed at amorphous carbon (a-C) layers.

Summary: Cytoprophet is a software tool that allows prediction and visualization of protein and domain interaction networks. It is implemented as a plug-in of Cytoscape, an open source software framework for analysis and visualization of molecular networks. Cytoprophet implements three algorithms that predict new potential physical interactions using the domain composition of proteins and experimental assays. The algorithms for protein and domain interaction inference include maximum likelihood estimation (MLE) using expectation maximization (EM); the set cover approach maximum specificity set cover (MSSC) and the sum-product algorithm (SPA). After accepting an input set of proteins with Uniprot ID/Accession numbers and a selected prediction algorithm, Cytoprophet draws a network of potential interactions with probability scores and GO distances as edge attributes. A network of domain interactions between the domains of the initial protein list can also be generated. Cytoprophet was designed to take advantage of the visual capabilities of Cytoscape and be simple to use. An example of inference in a signaling network of myxobacterium Myxococcus xanthus is presented and available at Cytoprophet's website. Availability: http://cytoprophet.cse.nd.edu Contact: cytoprophet@cse.nd.edu Supplementary information: Examples and supplementary data are accessible at http://cytoprophet.cse.nd.edu

International audience; We investigated the magnetic properties of thin magnetite and iron films grown on MgO(001) by means of hard x-ray photon-in photon-out probe, namely, 1s2p resonant inelastic x-ray scattering-magnetic circular dichroism (RIXS-MCD). A comparison of the spectra acquired from bulk and thin layer magnetite samples reveals their nearly identical shape. Hysteresis loops measured with RIXS-MCD also show a close similarity to the vibrating sample magnetometer profiles supporting the conclusion that the technique can be applied for the quantitative analysis of element and site specific magnetization in buried films containing transition metal elements. We show that Fe 1s2p RIXS-MCD is insensitive to the magnetic signal of iron impurities naturally dispersed in monocrystalline MgO substrates. The latter, combined with a unique feature of resonant inelastic x-ray scattering, namely the ability to tune incident and emitted photon (transfer) energy, allows us to separate the dichroic signal of metal layers from that of ferrite and, thus, to independently probe the magnetization of metal and oxide layers in multilayer systems

Temperature and magnetic field dependences of electrical conductivity are systematically studied in granular films (Fe45Co45Zr10) x (Al2O3)100−x (28 ⩽ x ⩽ 64) containing crystalline metallic α-FeCo-based nanoalloy cores encapsulated in an amorphous oxide shell embedded in an amorphous Al2O3 matrix. Formation of ‘metallic core–oxide shell’ nanogranules is confirmed by transmission electron microscopy (TEM) and HRTEM. The structure of core and shell is governed with the difference in the oxidation states of Fe and Co ions investigated with EXAFS, XANES and Mössbauer spectroscopy. A considerable negative magnetoresistance (MR) effect of spin-dependent nature is observed in the whole range of x values. Its increase with decreasing temperature is correlated with the magnetic saturation of superparamagnetic metallic nanogranules. The enhanced MR effect in ‘core–shell’ granular films is related to the percolation of oxide shells and their influence through spin filtering processes. A considerable high field MR at low temperatures and the resulting deviation of MR and squared magnetization are attributed to a magnetic randomness and/or strong magnetic anisotropy of the magnetic oxide shell.

We show that K-edge X-ray absorption spectroscopy can be used as a sensitive probe of electron correlations in V2O3. This is possible thanks to a detailed study of the V K pre-edge region while changing the thermodynamic parameters of the system. LDA+DMFT provides an interpretation of the changes in the electronic structure, in particular in the upper Hubbard band, at the Mott transition. The possibility of modifying the Coulomb interaction and observing the metal-insulator transition by applying an external pressure is also demonstrated, which is of particular interest for the study of many strongly correlated materials.

SnO2 gas sensors with palladium as additive in the range of 0.2 wt% and 3 wt% were studied by in situ X-ray absorption spectroscopy under idealized and real operating conditions. Simultaneously to the structural studies, measurements of the sensing properties were undertaken allowing for the determination of structure-function relationships. For this purpose a new in situ spectroscopic cell was designed which permitted on the one hand sensing on conventional screen printed 50 microm thick sensing layers and on the other hand structural analysis with X-rays provided by an insertion device at a 3rd generation synchrotron facility in fluorescence mode. Pd K-edge XANES and EXAFS results on gas sensors showed that palladium, present in an oxidized state, is finely dispersed if it is added in small quantities (0.2 wt%) while it forms clusters at higher concentrations (3 wt%). This is also reflected by the much easier reduction of palladium in the latter, higher concentrated ones. Under realistic sensing conditions (30-200 ppm H2; 10-50 ppm CO in dry and humid air at 200 and 300 degrees C) for the low additive concentration samples, no change in oxidation state was observed, i.e. palladium remained in its oxidized state. This has important consequences on the understanding and modeling of the gas sensing mechanism.

An additional reference is needed in the article Cytoprophet: a Cytoscape plug-in for protein and domain interaction networks inference. We include this reference as a matter of addendum. Contact: cytoprophet@cse.nd.edu

Charge and spin state evolution of the transition metals in the LaMn1−xCoxO3 perovskite series was studied by means of high resolution x-ray absorption and emission spectroscopy. The gradual charge transfer from Mn to Co sites was observed upon increasing Co doping. The high spin of the Mn3+∕4+ and Co2+ ions is preserved in the entire solid solution. Co3+ ions reveal low spin state at low doping, while the gradual increase of the average Co3+ spin state is observed at higher cobalt concentrations. The results plausibly explain the observed magnetization anomalies.

Spin and orbital magnetic moments of Re in AA'FeReO6 double perovskites (A,A' = Ba, Sr, Ca) have been directly probed employing XMCD spectroscopy at the Re L2,3-edges. A considerable orbital magnetic moment is observed in all the studied compounds despite octahedral coordination. Relative orbital to spin contribution per Re atom rises with lattice distortion from mL/mS = -0.28 to -0.34 for AA'=Ba2FeReO6 and Ca2FeReO6, respectively. A preliminary XMCD measurements at the Fe L2,3-edges reveals also a significant orbital moment of iron in Ca2FeReO6. The relation of the results to the magnetic properties of the compounds is discussed.